This invention generally relates to a leaf spring assembly and specifically to a method of relieving leaf spring mounting stresses.
Conventional leaf springs for vehicle suspensions comprise flat rolled steel strips having a substantially rectangular cross-sectional shape along a plane perpendicular to the longitudinal direction of each steel strip. The leaf spring assembly includes a clamped center portion for mounting of an axle and a suspension member. The suspension member is typically a coil or air spring to further absorb road inconsistencies. The highest stresses on the leaf spring are experienced in the clamped section of the leaf spring. Many stress relieving techniques and methods have been used in conventional leaf spring assemblies in order to reduce negative affects that high stress concentrations produce.
One conventional leaf spring assembly includes a short spring seat member and a single long leaf spring member. The long leaf spring member extends from a first mount to a second mount. The spring seat member extends to a central clamp securing the spring seat to the longer leaf spring. The axle or other suspension member is fastened at the center clamp. The highest stress within the long leaf spring occurs at the center clamp. The stress concentration at the center clamp is non-uniform across the leaf spring. The increased and non-uniform stress concentration typically results in reduced spring fatigue life.
Accordingly, it is desirable to develop a leaf spring assembly including stress-relieving features to uniformly distribute stresses and increase the overall fatigue life of the leaf spring assembly.